> ## Documentation Index
> Fetch the complete documentation index at: https://doc.lucidworks.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Parameterized Faceting Stage

export const schema = {
  "type": "object",
  "title": "Parameterized Faceting",
  "description": "Query Solr to determine the most frequent value for a given field (e.g. category) and then use that value to lookup stored parameters to auto-select the most appropriate facet for a query.",
  "required": ["facetField", "handler", "method"],
  "properties": {
    "skip": {
      "type": "boolean",
      "title": "Skip This Stage",
      "description": "Set to true to skip this stage.",
      "default": false,
      "hints": ["advanced"]
    },
    "label": {
      "type": "string",
      "title": "Label",
      "description": "A unique label for this stage.",
      "hints": ["advanced"],
      "maxLength": 255
    },
    "condition": {
      "type": "string",
      "title": "Condition",
      "description": "Define a conditional script that must result in true or false. This can be used to determine if the stage should process or not.",
      "hints": ["code", "code/javascript", "advanced"]
    },
    "facetField": {
      "type": "object",
      "title": "Facet Field",
      "required": ["field"],
      "properties": {
        "field": {
          "type": "string",
          "title": "Field",
          "description": "The field whose values you want to facet on."
        },
        "prefix": {
          "type": "string",
          "title": "Prefix",
          "description": "Prefix of terms to facet on."
        },
        "sort": {
          "type": "string",
          "title": "Sort",
          "description": "Ordering of the faceting results.",
          "enum": ["count", "index"]
        },
        "limit": {
          "type": "integer",
          "title": "Limit",
          "description": "Maximum number of facets to return."
        },
        "offset": {
          "type": "integer",
          "title": "Offset",
          "description": "Offset into list of resulting facets."
        },
        "minCount": {
          "type": "integer",
          "title": "Minimum Count",
          "description": "Lower threshold of term counts to be included.",
          "default": 1
        },
        "missing": {
          "type": "boolean",
          "title": "Count Missing",
          "description": "Optionally include a 'missing' facet bucket for documents without the selected field.",
          "default": false
        },
        "method": {
          "type": "string",
          "title": "Method",
          "enum": ["enum", "fc", "fcs"]
        },
        "enumCacheMinDf": {
          "type": "integer",
          "title": "Enum Cache Minimum DF",
          "minimum": 0,
          "exclusiveMinimum": false
        },
        "threads": {
          "type": "integer",
          "title": "Number of Threads",
          "minimum": 0,
          "exclusiveMinimum": false
        }
      }
    },
    "fallbackValue": {
      "type": "string",
      "title": "Fallback Value",
      "description": "Optional fallback value to use for the facet field if one cannot be determined by querying Solr."
    },
    "failQueryOnError": {
      "type": "boolean",
      "title": "Fail Query on Error",
      "description": "Fail the query request if an error occurs when processing this stage.",
      "default": false
    },
    "handler": {
      "type": "string",
      "title": "Request Handler",
      "description": "Solr query request handler to send the auto-facet query request to.",
      "default": "select"
    },
    "method": {
      "type": "string",
      "title": "HTTP Method",
      "description": "HTTP method used to send the auto-facet query request.",
      "enum": ["GET", "POST"],
      "default": "GET"
    },
    "params": {
      "type": "array",
      "title": "Additional Query Parameters",
      "items": {
        "type": "object",
        "required": ["key"],
        "properties": {
          "key": {
            "type": "string",
            "title": "Parameter Name"
          },
          "value": {
            "type": "string",
            "title": "Parameter Value"
          }
        }
      }
    },
    "headers": {
      "type": "array",
      "title": "Headers",
      "items": {
        "type": "object",
        "required": ["key"],
        "properties": {
          "key": {
            "type": "string",
            "title": "Parameter Name"
          },
          "value": {
            "type": "string",
            "title": "Parameter Value"
          }
        }
      }
    },
    "inherit": {
      "type": "boolean",
      "title": "Inherit Parameters From Parent?",
      "description": "Select box if a child category should inherit its parents' stored parameters.",
      "default": false
    }
  },
  "category": "Other",
  "categoryPriority": 1,
  "unsafe": false
};

export const SchemaParamFields = ({schema}) => {
  const sanitize = str => {
    if (typeof str !== "string") return str;
    return str.replace(/^"(.*)"$/s, "$1").replace(/\\/g, "").replace(/"/g, "'");
  };
  const formatDescription = str => {
    const s = sanitize(str);
    return (/[.!?]\)*$/).test(s) ? s : `${s}.`;
  };
  const {description, properties = {}, required: requiredProps = []} = schema;
  const visibleProps = useMemo(() => Object.entries(properties).filter(([, prop]) => !prop.hints?.includes("hidden")), [properties]);
  return <div>
      {description && <p>{formatDescription(description)}</p>}

      {visibleProps.map(([name, prop]) => {
    const isRequired = requiredProps.includes(name);
    const hasDefault = prop.default !== undefined;
    const rawDefault = prop.default;
    const isComplexDefault = hasDefault && (typeof rawDefault === "object" || typeof rawDefault === "string" && (rawDefault.length > 20 || rawDefault.includes('"')));
    const fieldProps = {
      key: name,
      body: prop.title || name,
      type: prop.type,
      ...prop.title && ({
        post: [<><span className="text-stone-400 dark:text-stone-500">API property: </span>{name}</>]
      }),
      ...isRequired && ({
        required: true
      }),
      ...!isComplexDefault && hasDefault ? {
        default: sanitize(String(rawDefault))
      } : {}
    };
    const isObject = prop.type === "object" && prop.properties;
    const isArrayOfObjects = prop.type === "array" && prop.items?.type === "object" && prop.items.properties;
    return <ParamField {...fieldProps}>
            {prop.description && <p>{formatDescription(prop.description)}</p>}

            {isComplexDefault && <div className="flex">
                <p>
                  <strong>Default:</strong>
                </p>
                <pre className="!my-0">
                  <code>
                    {JSON.stringify(rawDefault, null, 2)}
                  </code>
                </pre>
              </div>}

            {isArrayOfObjects && <div className="flex">
              <p>
                <strong>Object attributes:</strong>
              </p>
              <pre className="!my-0">
                <code>
                  {'{\n'}
                  {Object.entries(prop.items.properties).map(([iname, iprop]) => <>
                      {`  ${iname}`}
                      {prop.items?.required?.includes(iname) && <span style={{
      color: 'red'
    }}> required</span>}
                      {`: {\n    display name: ${sanitize(iprop.title || '')}\n    type: ${iprop.type}\n  }\n`}
                    </>)}
                  {'}'}
                </code>
              </pre>
              </div>}

            {isObject && <Expandable title="properties">
                <SchemaParamFields schema={{
      properties: prop.properties,
      required: prop.required
    }} />
              </Expandable>}
          </ParamField>;
  })}
    </div>;
};

export const LwTemplate = ({title = "Key questions to get you started", icon = "sparkles", cta = "Powered by Agent Studio", linkHref = "https://lucidworks.com/demo/?utm_source=docs&utm_medium=referral&utm_campaign=docs_cta_ai"}) => {
  const [isLoaded, setIsLoaded] = useState(false);
  useEffect(() => {
    const timer = setTimeout(() => {
      setIsLoaded(true);
    }, 500);
    return () => clearTimeout(timer);
  }, []);
  return <div className="lw-template-container">
      <Card title={title} icon={icon}>
        {isLoaded && <span dangerouslySetInnerHTML={{
    __html: `<lw-template id="a029c1a9-28be-427e-b0e1-5d918920246a"></lw-template
            >`
  }} />}
        <Link href={linkHref} className="agent-studio-link text-left text-gray-600 gap-2 dark:text-gray-400 text-sm font-medium flex flex-row items-center hover:text-primary dark:hover:text-primary-light group-hover:text-primary group-hover:dark:text-primary-light">Powered by Lucidworks Agent Studio</Link>
      </Card>
    </div>;
};

[localhost link]: http://localhost:3000/docs/4/fusion-server/reference/pipeline-stages/query/parameterized-faceting-query-stage

[mintlify link]: https://doc.lucidworks.com/docs/4/fusion-server/reference/pipeline-stages/query/parameterized-faceting-query-stage

[old doc.lw link]: https://doc.lucidworks.com/fusion-server/4.2/255

The Parameterized Faceting query pipeline stage determines the most frequent value for a given field, then uses that value to look up stored parameters and auto-select the most appropriate facet for a query.

<LwTemplate />

## Configuration

<Tip>
  When entering configuration values in the UI, use *unescaped* characters, such as `\t` for the tab character. When entering configuration values in the API, use *escaped* characters, such as `\\t` for the tab character.
</Tip>

<SchemaParamFields schema={schema} />